WSL1 was "Linux API on top of Windows", WSL2 is "Linux VM on top of Windows"
WSL1 was "Linux API on top of NT kernel picoprocesses", WSL2 is "Linux VM on top of Hyper-V"
https://www.microsoft.com/en-us/research/project/drawbridge/
https://learn.microsoft.com/en-us/archive/blogs/wsl/windows-...
https://www.zdnet.com/article/under-the-hood-of-microsofts-w...